Twisting of continuous filament yarns



Aug. 2, 1960 R. s. c. ARRIDGE ETAL 2,947,136

TWISTING OF CONTINUOUS FILAMENT YARNS Filed March 25, 1958 Inventorsfioeier GRIP/mm Clmwrwc/c flak I065 GEORGE #45527 Claus y Nap/21s14641.14: PELL 9 y 2 Z Attorneys 2,917,136 U 'rwrs TING or CONN "arm'sFAILAHMRN nubertl G. A r ds an G ne A-HC oi s u Pq w ii i ii, E la an Mr w l i 'Pr l, M lb u en tralia, assignors to British Nylon SpinnersLimited,

rdm pao nnguna H v a Filed Mar. 25, 1958, Star. Nb. 723,766 Claimspriority, as irant. Great lliitiiiii Mia 60', 1 957- The presentinvention concerns improvements inorie lating to the twisting ofeohtinnousfilament arns, and has particular reference t'o the processofiiptwis'tin g such yarns when composed of a plurality of filaments.

In the process of uii-tvviStih'g, asupply package in the form of abobbin is rotated at high speed on'a Vertical spindle and the yarn isled off over the top end of the bobbin, through a balloon guidepositioned at the required distance directly above the spindle, and isthen wound up in a package such as "a cheese. The rapid rotation ofthe-bobbin causes the yarn to balloon between the point of take-off andthe balloon guide; and, depending principally on the vertical positionof the point of takeoff, the supply package geometry (i.e. the shape'andsize) and the speed of rotation, the balloon formation at any time maybe either single, or multiple in nature; That is to say that, for amultiple balloon, the yarn atany one instant between the take-elf pointand-the balloon-guide will tracefout a roughly sinusoidal path;"Depending on the nature of the balloon, the. tension in the yarn in theballoon (but not the twist imparted) will vary; and. for multipleballoons; the tension may be half orv less than that found when the.yarn isin a singleballoon.

In such a process of up'rtwisting, it will be appreciated that thedesired resultant twist is achieved only at or about the take-up pointof theyarn on the receiving package, and th o h l rofi. Po nt f thetyarn, fromvth'e supp package to the take-up pQ nUhq amount of-twistpresent increases from zero to themaximum, h n Oneditficulty that isencountered when' the,yarn is required to be twisted to only alow-degr;ee',;e;g. between about 2 and about 1.0 turns per inch,is;thatjthe;amount of twist inserted in the, region of the take loifpoint may be insufiicient to; keep the filamntsbound tightly together,certainly when the yarn is in a multiple ballooning phase. As a result,loops of filaments comprising either single slack filaments, or aplurality of slack filaments, are

formed in the yarn atjodd intervals along its length, and the presenceof these loops is often detrimental to the satisfactory use oftheyarn im-subsequent knitting, we'aving, braiding or other textile operations. IWhen inserting a high degree of twist insuch a yarn, the defect oflooping does not normally occur, because the amount of twist in thelower region i f above, say, turns per inch for 60 denieryarns andbelow,'is suflicient to bind all the filaments firmly togetherintoonecoherent structure, With high twists, other difii culties,relating-toy talke-oif may occur, but theydo not concerntthe present invention,except insofar as the conditions, for, operation of the presentinvention should be such as to avoid such difiiculties.

The present invention jfor it s ObiQlc t the preyention of substantiallyall, orga1l,-;sl1h;l0ops;being formed vin a ldw twist multifilament yarnduring-'up-twisting to a'lowdegree. l Y, M I I y Accordingly, inigeneralterms,- the invention provides, in pp r for p w ting y ns, mean tfcradding at porary twist to yarn which is in the ballooning phase.

ired States Patent ice 4 23,947,135 Asa-acre The invention alsocomprises a process for upt'wisting a continuous filament yarn wherein afalse twist is imparted to the yarn so as to reinforce the twist in thatpart of the yarn which is in the ballooning phase. The false twistshould be such that individual filaments of the said yarn-are boundtogether sufiiciently firmly to prevent them from looping to anysubstantial extent. A total twist of some -30 turns per inch for yarnsof 60 denier and below is preferred in the yarn in the ballooning phase.According to a convenient embodiment of'this invention which will bemore fully described hereaftera temporary reinforcing twist is added inan tip-twisting process by means of an annular friction surface makingcontact with the outward-facing parts of the at a position at or justbelow a balloon guide. The effect of the ballooning motion of the yarnin contact with the friction surface is to cause the yarn to be rolledaround the surface and thus to be rotated about its own axis. In thismannena false twist, reinforcing the true twist, is inserted into thesuccessive lengths of yarn between the friction surface and the point oftake-01f from the supply bobbin. Bya suitable choice of the nature ofthe friction surface and its positioning, this reinforcing twist can bemade suflicient substantially to prevent any looping.

Conveniently, the friction surface can take the form of a rubber(natural or synthetic), or rubber-lined ring, through which the yarn ispassed and with which the yarn makes contact just before its entry tothe balloon guide. There will now be given a more complete descriptionof the aforesaid embodiment with reference to the accom- 'p'anyingdrawings, in which: a

Figure l is a diagrammatic 'side'elevation, of the said convenientembodiment of the invention;

Figure 2 shows a combined balloon guide and ring holder used in thisembodiment; H a

Figure 3- shows a rubber ring for fitting in the holder of FigureZ;

Figure4 is a section through the ring of Figure 3.

Referring to Figure 1, an upstanding spindle 1 is rotated at high speedand carries round with it a yarn package 3, Due to the speed ofrotation, yarn 5 forms a balicon on being led upwardly through a balloonguide 7 positioned heightwise above the spindle. This guide 7 is formedby one end of a thick wire comprising a combined balloon guide and ringholder 9 (see also Figure 2) which is pivotally mounted on the machineat its other end. Within the ring-holder 9 is mounted a rubber (naturalor synthetic) ring or amiulus 11 (see also Figures 3 and 4) whichthereby provides means for imparting a false-twist to yarn as willbecome more clear hereinafter. Traverse mechanism 13, comprises a rod 17pivot-ally mounted on a reciprocating shaft 15, and having a yarn guide19 for laying the yarn directly on a take-up package (cheese) 21, whichis driven by contact with drive roll 23, the above apparatus togethercomprising the 'yarn takeup mechanism. I p

The yarn is led upwardly from balloon guide 7 to a guide 25 on therearward portion of the traverse mechanism 13, and thence is laid downon the cheese 21 by the guide 19 I V v Referring particularly toFigures3 and 4, it will be seen that the ring or annulus 11 has arounded lip 27 where the '7 abovering 11, are shown diagrammaticallysince such distances should be selected to give the required angle ofwrap of the yarn S'around the rounded'portion 27-of ring 11. Thisdistance will depend on the nature of the material of ring 11 and on thedesired amount of false twist to be inserted. The twist inserted bycontact with ring 11 will be in the same direction as and will reinforcethe true twist in the yarn in those successive portions of it betweenthe ring and the package 3. That is to say that the twist on the supplyside of ring 11 will extend back to the supply package 3. This twist,due to the forward motion of yarn 5, will disappear from the yarn almostimmediately after the yarn has emerged above the ring 11, so that theyarn will be wound up with only the required amount of low twist in itsay, between about 2 and about 10 turns per inch brought about by theconditions of up-twisting. The amount of false twist required .to beinserted will depend on the nature of the yarn, i.e. its composition,the number and the denier of the individual filaments, the presence orabsence of size etc.; but should be such that, together with the truetwist inserted,

the amount of twist in the ballooning yarn is at least 15 turns perinch, and preferably about 20-30 turns per inch. A very much highertotal twist is undesirable owing to the take-off complications that arethereby introduced.

'It is, of course, possible to arrange that the ring is rotated so as toinsert a greater or lesser amount of false twist in the yarn, dependingon the direction of rotation, than would be the case if it werestationary. The direction of rotation would need to be contrary to thatof the ballooning yarn if it were desired to increase the twistingeffect of the ring. Yet again, the balloon guide itself can be adaptedto hold a rubber grommet from which the yarn must be caused to emergesubstantially axially, the grommet having a hole-size of sufiicientdiameter to ensure that the yarn will have a rolling motion imparted toit by contact with the internal surface thereof.

The amount of false twist inserted by any given friction surface in anygiven process will be dependent on the nature of the friction surface,theangle of wrap of the yarn in contact'with the surface, and thetension in the yarn between the surface and the take-off point. The twolatter functions will vary according to the mode of balloon effective atany given time. In practice, however, it is found that the variationsare complementary, so that the value of twist tends to remainsubstantially constant and sufficient for the purpose if the nature ofthe friction surface is correct. By a sufficiently high positioning ofthe balloon guide and friction surface, it is possible to arrange thatthe balloon is always in a multiple phase, and thus cause the tension inthe yarn to remain constantly at a very much lower figure than normal.

It may sometimes be desirable to arrange that the yarn I makes contactwith the friction surface only under certain COHdIIIOIIS, e.g.- when theyarn is-leaving the bobbin from the upper half only of a supply packagewhich is tapered at both ends. Otherwise, a re-entrant balloon may becaused to form at the lower end of the package and lead to snarling ofthe yarn. To achieve this with a rubber ring attachment, a second smoothmetal ring, of slightly larger internal diameter than that of the rubberring, may be mounted for limited heightwise reciprocatory motion,synchronised with the yarn take-off traverse motion, below the rubberring. It is arranged that the metal ring, when in its lower position,shall contact the ballooning yarn in such a way that the yarn is removedfrom contact with the internal surface of the rubber ring; and themovement of the metal ring is timed so that it occupies its lowerposition during the time that the yarn is coming off the supply packageat the lower tapered end-portion thereof. In this way, the rubber ringis prevented from operating during the time that the yarn is coming offthe lower tapered end-portion, and the metal ring, which'may bechromiumplated, is too smooth either to affect the running of the yarnor to cause the yarn to rotate about its axis so as to insert falsetwist.

Any material having a sufiiciently high coefiicient of friction with theyarn concerned and having a sufiiciently durable nature is suitable forthe friction surface described 5 above. Naturally, however, it shouldnot be of a nature that might impair the strength or appearance of theyarn,

the use of such rings.

or might actually abrade the yarn so as to sever any filaments thereof.Vulcanised natural rubber with carbon black filler has provedsatisfactory with synthetic linear polyamide continuous filament yarnsof from 30 to 210 denier, having individual filament deniers of 3 or 6denier. Prescollan polyester rubber, and neoprene synthetic rubber offrom 50 to Shore hardness are possibly more suitable materials for thefriction surface owing to their wearing qualities. It is found, also,that, due probably to the extra twist assisting in the actual withdrawalof the yarn from the supply bobbin, and due to the greater amount oftime that the balloon is in a multiple phase, the tension in the yarn atwind-up is actually less-than in the ordinary case, and thus a softercheese can be wound. This is advantageous in the case of nylon yarns,particularly, as it is desirable to wind the cheeses as softly aspossible to allow for subsequent contraction of the yarn.

Other means of inserting false twist into the ballooning yarn may beemployed, but they are not normally as convenient or simple as thepreferred rubber ring. Such means may take the form of a conventionalfalse-twisting spindle or of a rotating rubber bush, positioned eitherabove or below the balloon-guide.

Example 1 Nylon 60 denier 20 filament yarn having &2 twist was uptwistedfrom a double taper drawtwist bobbin to '7VzZ turns per inch. The bobbinwas rotated at 9,000 -r.p.m. on a vertical spindle, and the twisted yarnwas wound up in cheese form at feet per minute. The wound length of thebobbin was 8 inches, and the distance between the top of the bobbin andthe balloon guide directly above the spindle was 1% inches. Positionedinch below the balloon guide was a rubberlined'ring of vulcanisednatural rubber with carbon black filler of /2 inch internaldiameter,which made continuous contact with'the ballooning yarn so as to insertfalse twist therein. The cheese so wound was softer than normal and hadno loops of filaments therein.

'denier 20 filament yarn of /2Z twist was uptwisted from a double taperdrawtwist bobbin to 72 turns per inch. The conditions were the same asin Example I with the exception that the ring was of neoprene syntheticrubber of 75 Shore hardness and of inch inner diam- Also running for thesame period was a control supply bobbin but having no ring to insertfalse-twist. There 'were over 3 times as many loops in the uptwistedcontrol yarn as there were in the yarn uptwisted through :the neoprenering.

Example III Nylon 60 denier 20 filament yarn of zero twist on /2 ,lb.double-flanged bobbins was uptwisted to 5 turns per inch Z twist. Thespeed of the supply package spindles was 9,000 r.p.m., and the linearspeed of the yarns wound up was feet/minute. 17 supply packages wereuptwisted with inch inner diameter fneoprene rings of 60 Shore hardnesspositioned 1 inch below the balloon-guide inserting false twist in theballooning yarns; and 17 supply packages were uptwisted without From thelatter batch'of packages, three had to be rejected after uptwisting, onaccount ofmulti and single-filament loops None of the yarnsuptwistedwith the use of the neoprene rings was defective in this manner.'

Although 60 denier nylon yarns havebeen referred to :in the aboveexamples, it must be made clear that the invention isof use for otherdeniers of nylon; and that Qlher continuous filament yarns, such asthose of Terylene polyester fiber of 75 denier have been success-' fullyuptwisted according to the invention, which may, accordingly, be usedwith them also.

It is also possible for the invention to form part of an uptwisterarrangement working at very hig arn throughputs of the order of 1000feet/minute and in which only some 1 or 2 turns per inch are required tobe inserted in the continuous filament yarn. In such circumstances, itmay be essential to rotate the rubber ring in order that the necessaryamount of false-twist may be inserted in the rapidly moving yarn.

What we claim is:

1. A process for uptwisting continuous filament yarn to about 2-10 turnsper inch, comprising: withdrawing yarn upwardly from a rapidly rotatingsupply package to form a thread balloon; imparting a false twist of atleast five turns'per inch to the succeeding lengths of yarn in theballooning phase, such that the total twist of the yarn in theballooning phase is at least fifteen turns per inch; and collecting theyarn.

2. A process according to claim 1 in which the amount of false-twist issuch that the total'twist in the yarn that is in the ballooning phase isof the order of 20-30 turns per inch.

3. A process according to claim 1 in which the falsetwist is generatedby passing the ballooning yarn in contact with a surface having a highcoeflicient of friction with the yarn.

4. In a process for uptwisting continuous filament yam to about 2-10turns per inch, including forming a thread balloonythe improvementcomprising imparting a falsetwist of at least five turns per inch tothat part of the yarn in the ballooning phase, such that the total twistof the yarn in the ballooning phase is at least fifteen turns per inch.

5. In a process for uptwistingcontinuous filament yarn to about 2-10turns per inch, including forming athread balloon; the improvementcomprising rotating the yarn in the ballooning phase about its own axisand thereby imparting a false-twist of at least five turns per inch tothe same, such that the total twist of the yarn in the ballooning phaseis at least fifteen turns per inch.

6. In a process'for uptwisting continuous filament yarn to about 2-10turns per inch, including forming a thread balloon; the improvementcomprising passing succeeding lengths of yarn in the ballooning phase incontact with a confining surface having a high coelficient of frictionwith the yarn, thereby imparting a reinforcing false-twist of at leastfive turns per inch to the yarn in the ballooning stage by rotating thesame about its axis, such that the total twist of the yarn in theballooning phase is at least fifteen turns per inch.

7. A process as in claim 5, wherein the false-twist is imparted to theyarn in the same direction as the true twist.

8. A process for uptwisting continuous filament yarn to about 2-10 turnsper inch, comprising the steps of; continuously withdrawing yarnupwardly from a rapidly rotating supply package through a guidepositioned above said package, whereby a thread balloon is formed; andcausing a portion of the ballooning yarn to pass in contact with asurface having a high coefl icient of friction with the yarn, wherebythe yarn is rotated by friction with the surface about its axis and areinforcing falsetwist of at least five turns per inch is imparted tothe yarn in the ballooning phase, such that the total twist of the yarnin the ballooning phase is at least fifteen turns per inch.

References Cited in the file of this patent UNITED STATES PATENTS2,227,910 Pool Jan. 7, 1941 2,232,542 Lewis Feb. 18, 1941 2,249,777Naumann et a1 July 22, 1941 2,258,899 Little et al. Oct. 14, 19412,318,162 Jones et al. May 4, 1943 2,718,111 Brown Sept. 20, 19552,803,105 Stoddard et al. Aug. 20, 1957 2,803,108 Stoddard et al. Aug.20, 1957 2,803,109 ,Stoddard et al. Aug. 20, 1957 2,823,513 Vandamme etal. Feb. 18, 1958 2,838,903 Sutter June 17, 1958 2,878,637 Bacon Mar.24, 1959 OTHER REFERENCES Frictional Properties of Nylon Yarn and TheirRelatidn to the Function of Textile Guides, by Baird et al., pagel01-page 111 of the Textile Institute Journal Pro- 5 ceedings, volume46, January-June 1955.

